1. Field of the Invention
The present invention relates to a receiver for receiving what is called a radio data system (RDS) broadcasting and, more particularly, to a broadcasting station selecting method to select a station by using program type information (PTY code).
2. Description of Background Information
Such an RDS broadcasting relates to a multiplex broadcasting in which additional information highly valuable in a radio installed in a car or the like is superimposed to a voice signal. The additional information includes station selection information, traffic information, and the like which are necessary to specify a broadcasting station located in the area and is standardized as a format regarding the RDS broadcasting.
In addition to the voice signal, the data format of such an RDS broadcasting includes additional information such as program identification information (PI code), a group type code, a PTY code, and the like. Among them, the PTY code plays a role to identify a type of the program (music program, news program, sports program, or the like). A list of its allocation is shown in Table 1.
TABLE 1 ______________________________________ Code Number PTY Code Contents of program types ______________________________________ 1 00000 No program 2 00001 News 3 00010 Current events 4 00011 Animated cartoon 5 00100 Sports 6 00101 Education 7 00110 Program for children 8 00111 Program for young adults 9 01000 Religious program 10 01001 Drama 11 01010 Rock music 12 01011 Light music 13 01100 Serious music 14 01101 Jazz 15 01110 Folk music 16 01111 Variety 17-31 Undefined 32 11111 Emergency broadcasting ______________________________________
An ordinary vehicle mounted radio receiver is designed by assuming that the handling thereof may be performed by a user who is driving in a car. In order to simplify the operation, therefore, operation keys in the form of push buttons are used (e.g., what are called 1-6 keys, specifying a broadcasting station by a six kinds of numbers are generally used). By previously storing specific broadcasting station information in correspondence to the operation key, afterwards the broadcasting station can be easily selected by depressing the operation key. The numbers assigned to the operation keys (hereinbelow, referred to as channel numbers) are made correspond to the broadcasting stations in a one-to-one relation.
Hitherto, a receiver for searching (retrieving and receiving) a broadcasting wave of desired broadcasting contents by a simple operation by using the PTY code has been developed (Japanese Patent Kokai No. 4-336809). In a station selecting process by the searching operation of such a receiver, the user at first instructs a program type by the operation key. The PTY code (hereinafter, referred to as a comparison PTY code) which is formed from the program type is compared with the PTY code of the additional information according to the RDS broadcasting that was selected and demodulated by a tuner. A control section of the receiver controls the tuner and receives the PTY code of the received broadcasting wave. In the event that the PTY code of the RDS broadcasting and the comparison PTY code are not identical, the control section retrieves a broadcasting station of another frequency. The above operation is continued until both of the PTY codes coincide.
There are 32 kinds of information regarding the program types as shown in Table 1. In order to designate the program types in correspondence to all of the PTY codes, consequently, 32 operation keys must be provided. Since an operation panel of the radio receiver installed in a car is not wide, however, a method is generally adopted in which presetting of only necessary PTY codes (for example, only six kinds) is performed by the respective operation keys. The receiver, therefore, has a memory regarding the PTY codes (hereinbelow, referred to as a PTY memory) and, ordinarily, a corresponding comparison PTY code is called by the channel number designated by the operation key, thereby performing the searching operation.
FIG. 1 shows a memory construction of the conventional PTY memory. As shown in FIG. 1, the PTY code representing a desired program type is stored in correspondence to the number of operation keys. The RDS receiver retrieves and receives the waves of the broadcasting station broadcasted by the desired program type by using the PTY memory.
As mentioned above, a receiver which doesn't have a memory like a PTY memory to make the channel numbers and the PTY codes correspond and selects a station by a memory to directly store the PTY codes and the frequency information and PS codes and the like of the receiving station according to the PTY codes has been disclosed in Japanese Patent Application Kokai No. 63-136828.
According to the construction of the above-mentioned conventional PTY memory, however, there is an inconvenience such that a plurality of PTY codes cannot be stored for each of the channel numbers.
It is now considered how the user using the PTY codes of the RDS broadcasting selects the broadcasting station depending on the program type.
First, there is a case of selecting the station of only a specific program type (for example, news, jazz, or the like). The conventional PTY memory managing method can cope with such a case. In case of considering the programs as groups classified by the genre, for example, desires in case of mainly collecting information, in case of listening to any music, in case of shaking off sleepiness by mainly listening to talking programs, and the like are naturally considered.
According to the construction of the conventional PTY memory, since there is the above inconvenience such that one channel number and one operation key are allocated to each PTY code, the user must specify and operate the operation key allocated to one of the genre. For example, even if the user wants to listen to any music, he once decides "jazz" by himself and operates the operation key of the corresponding channel number.
In general, however, since the user frequently selects the station by separating to a desired genre (for example, classification such as "music", "news relation") rather than he desires a specific program type it will be convenient if the station can be selected by using a group in which a plurality of PTY codes are collected as a unit.
According to the conventional PTY memory, the PTY codes are stored in correspondence to the channel numbers (FIG. 1).